Ultrasonic echoes from deliberately launched diagnostic sound waves into tissue are attenuated in proportion to the distance that the sound waves must travel to reach the reflector, plus the distance that the resulting echoes must travel back to reach the receiver. Since sound waves are attenuated as they pass through the human body, the deeper the penetration, the greater the attenuation.
The ultrasound diagnostic imaging profession uses a substance called a "coupling medium" to enhance transmission of the sound waves between the machine (transducer) and the patient. This medium is most often an aqueous gel. Industry standard containers for this gel are pliable thermoplastic bottles, having a capacity of approximately 0.25 liters. The aqueous gel is applied liberally to the skin area of the patient where the transducer will be in contact.
It is desirable to keep this coupling gel at or near body temperature so that patient discomfort is reduced when the gel is applied to the patient. Most often, the temperature of the coupling medium is raised and maintained through the use of special stand-alone, electrical heating devices. These use their own electrical connection (short cord) to receive power and heat the container of coupling medium to about 35.degree. C. and are usually located on a counter or table in an examination room or clinic.
Unfortunately, this requires the operator to leave the ultrasound machine to get the gel. Consequently, many operators, desiring to keep the gel more readily available, simply keep it on or near the ultrasound equipment. Of course, then the gel is not warming, and the patient has uncomfortably cool gel applied to his or her skin.
In an effort to provide convenience for the operator, numerous locations have been provided for the operator to place the container of coupling gel between applications on patients. However, the problem with many of these locations is that even though the coupling medium is conveniently placed for the sonographer to reach and apply it to the patient, the medium is no longer being maintained at an elevated temperature and must be returned to its special heating device for re-warming.
It would be desirable then to have a convenient, on-the-machine storage location for the coupling medium which raises the temperature of the medium and maintains it at a comfortable level for use.